Injection blow molding apparatus

ABSTRACT

An injection blow molding apparatus comprises: a first oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from an oil tank to an injection mold drive unit provided in an injection mold unit; and a second oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from the oil tank to a blow mold drive unit provided in a blow mold unit, the second oil supply section being provided independently of the first oil supply section.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/521,166, filed Apr. 21, 2017, which is a National Stage Entry ofInternational Application No. PCT/JP2015/080024, filed Oct. 23, 2015,which claims priority from Japanese Patent Application No. 2014-217642,filed Oct. 24, 2014. The entire contents of the above-referencedapplications are expressly incorporated herein by reference.

TECHNICAL FIELD

This invention relates to an injection blow molding apparatus forproducing a hollow container made of resin. Concretely, the inventionrelates to a one-stage injection blow molding apparatus improved inenergy saving properties and low-noise properties.

BACKGROUND ART

Various methods for molding hollow containers composed of resinmaterials have been proposed so far. A typical method of them is aninjection blow molding method which comprises forming a preform(parison) by injection molding, and blow molding this preform to form ahollow container.

An injection blow molding apparatus adopting this injection blow moldingmethod has an injection molding section equipped with an injectiondevice (injection unit) and an injection mold, and a blow moldingsection equipped with a blow molding machine and a blow mold. In theinjection molding section, a resin material is injected by the injectiondevice into the injection mold to form a preform. In the blow moldingsection, the preform accommodated in the blow mold is blow molded by theblow molding machine to form a hollow container. Such an injection blowmolding apparatus is called, for example, a one-stage or hot parisoninjection blow molding apparatus.

The injection blow molding apparatus generally moves the injection moldand the blow mold by actuators composed of hydraulic cylinders or thelike to carry out mold clamping. Each actuator is supplied with oil froman oil tank by a hydraulic drive source which has a plurality of, forexample, 2 to 3 fixed pumps and one induction motor. In recent years,injection blow molding apparatuses have appeared which reduce energyconsumption during molding, for example, by adopting a hydraulic drivesource including one or two variable pumps, which have been changed fromthe two to three fixed pumps, and an induction motor combined therewith.However, a further improvement in the energy saving properties of theinjection blow molding apparatus is desired.

To meet such a desire, a proposal has been made for an injection device(injection unit) constituting an injection molding apparatus, theinjection device having, for example, a hydraulic drive source whichincludes a fixed discharge hydraulic pump and a drive motor (e.g., servomotor) for driving this hydraulic pump, and which controls therotational speed of the drive motor to control the discharge flow rateand the discharge pressure of the hydraulic pump (see, for example,Patent Document 1).

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent No. 3455479

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

By adopting such an injection unit (injection device), the energy savingproperties of an injection blow molding apparatus can be improvedfurther.

The above-described pressure drive source is known to consume lessenergy than does a pressure drive source equipped with variable pumpsand an induction motor. Thus, it is conceivable to also employ theaforementioned pressure drive source having hydraulic pumps and a drivemotor, as an oil supply section for supplying oil to each of actuatorsconstituting devices other than an injection device of an injection blowmolding apparatus.

The injection blow molding apparatus, however, often has a large numberof actuators to be operated, and involves complicated hydrauliccircuits. To improve the energy saving properties of the injection blowmolding apparatus, therefore, it is not sufficient for the injectionblow molding apparatus to have a single oil supply section (pressuredrive source) as in the case of a single injection unit (injectiondevice). Instead, the injection blow molding apparatus needs to have aplurality of oil supply sections (pressure drive sources).

The present invention has been accomplished in the light of theforegoing circumstances. It is an object of the invention to provide aninjection blow molding apparatus aimed at improving energy savingproperties by appropriately providing a plurality of oil supplysections.

Means for Solving the Problems

A first aspect of the present invention, intended to solve the aboveproblems, is an injection blow molding apparatus including an injectionmolding section which is equipped with an injection unit and aninjection mold unit to be operated by an oil pressure and which forms apreform by injection molding, and a blow molding section which isequipped with a blow mold unit to be operated by an oil pressure andwhich blow molds the preform, the injection blow molding apparatuscomprising: a first oil supply section which has a hydraulic drivesource composed of a drive motor, whose number of revolutions can becontrolled, and a hydraulic pump and which supplies oil from an oil tankto an injection mold drive unit provided in the injection mold unit; anda second oil supply section which has a hydraulic drive source composedof a drive motor, whose number of revolutions can be controlled, and ahydraulic pump and which supplies oil from the oil tank to a blow molddrive unit provided in the blow mold unit, the second oil supply sectionbeing provided independently of the first oil supply section.

A second aspect of the present invention is the injection blow moldingapparatus according to the first aspect, further comprising: a third oilsupply section which has a hydraulic drive source composed of a drivemotor, whose number of revolutions can be controlled, and a hydraulicpump and which supplies oil from the oil tank to an injection drive unitprovided in the injection unit, wherein the first oil supply section andthe second oil supply section are provided independently of the thirdoil supply section.

A third aspect of the present invention is the injection blow moldingapparatus according to the first or second aspect, wherein the drivemotor is a servo motor.

A fourth aspect of the present invention is the injection blow moldingapparatus according to any one of the first to third aspects, whereinthe injection mold unit comprises an injection mold including a neckmold for forming a neck portion of the preform, an injection core moldfor forming the inner shape of the preform, and an injection cavity moldfor forming the outer shape of a barrel portion of the preform; theinjection mold drive unit includes an opening/closing drive portion foropening and closing the injection mold, a raising/lowering drive portionfor raising and lowering the neck mold with respect to the injectioncavity mold, and a mold clamping drive portion for clamping theinjection mold which has been closed; and the first oil supply sectionsupplies oil from the oil tank to the opening/closing drive portion, theraising/lowering drive portion, and the mold clamping drive portion.

Effects of the Invention

According to the present invention described above, the plurality of oilsupply sections each having the pressure drive source composed of theoil pump and the drive motor are appropriately provided for theplurality of drive units. Thus, the blow molding apparatus improved inenergy saving properties can be realized. Furthermore, noises duringoperation of the injection blow molding apparatus can be reduced. Thatis, the low-noise properties of the injection blow molding apparatus canalso be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the schematic configuration of aninjection blow molding apparatus according to an embodiment of thepresent invention.

FIG. 2 is a front view showing the schematic configuration of aninjection mold unit according to the embodiment of the presentinvention.

FIG. 3 is a side view showing the schematic configuration of theinjection mold unit according to the embodiment of the presentinvention.

FIG. 4 is a view showing the schematic configuration of a blow moldaccording to the embodiment of the present invention.

FIGS. 5A, 5B are hydraulic pressure waveform charts showing changes overtime in a command pressure and an actual pressure in an injectionmolding step.

MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will now be described in detailby reference to the accompanying drawings.

An injection blow molding apparatus 10 according to the presentembodiment shown in FIG. 1 is a so-called one-stage apparatus, andcomprises an injection molding section 20 for injection molding apreform (not shown), a temperature control section 30 for performing thetemperature control of the preform, a blow molding section 40 for blowmolding the preform to form a hollow container which is a final moldedproduct, and a withdrawal section 50 for taking the hollow container outof the apparatus.

The injection molding section 20 is composed of an injection device 60for injecting a resin material, and an injection mold unit 70 includingan injection mold 71 installed to be adjacent to the injection device60.

The injection device 60 incorporates an injection screw 62 in aninjection cylinder 61, and has an injection drive unit 63 for rotatingand advancing the injection screw 62. The injection drive unit 63 iscomposed of an injecting hydraulic motor 64 and an injecting hydrauliccylinder 65 which serve as actuators. The injection device 60 isdesigned to carry out injection by retreating the injection screw 62while rotating it by the injecting hydraulic motor 64 to charge apredetermined amount of the resin material ahead of the injection screw62 and, after completion of the charging, advancing the injection screw62 by the injecting hydraulic cylinder 65.

The injection mold unit 70 is equipped with the injection mold 71, andan injection mold drive unit 72. As shown in FIGS. 2 and 3, theinjection mold 71 includes a neck mold 73 for forming a neck portion ofa preform 1, an injection core mold 74 for forming the inner shape ofthe preform 1, an injection cavity mold 75 for forming the outer shapeof a barrel portion of the preform 1, and a hot-runner mold 76 fordistributing and guiding molten resin, which has been supplied from theinjection device 60, into the injection cavity mold 75 that has beenclamped.

The injection mold drive unit 72 has an opening/closing drive portion(high speed opening/closing mechanism) 77 for opening and closing theinjection core mold 74 constituting the injection mold 71 at a highspeed; a raising/lowering drive portion (raising/lowering mechanism) 78for raising and lowering the neck mold 73 with respect to the injectioncavity mold 75; and a mold clamping drive portion (high pressure moldclamping mechanism) 79 for clamping the closed injection mold 71 at ahigh pressure.

The opening/closing drive portion 77 has actuators 77 a composed ofhydraulic cylinders to be driven by an oil pressure, and opens andcloses the injection mold 71 by use of the actuators 77 a as a powersource. For example, the opening/closing drive portion 77 lowers andraises the injection core mold 74, with the use of the actuators 77 afixed inside a machine stand 80 as a power source, thereby closing andopening the injection mold 71. In detail, the actuators 77 a lower andraise an upper movable platen 81, to which the injection core mold 74has been fixed, via a lower moving plate 83 and tie bars 84 with respectto the injection cavity mold 75 and the hot-runner mold 76 installed onthe machine stand 80.

The raising/lowering drive portion 78 has an actuator 78 a, such as ahydraulic cylinder fixed inside the machine stand 80 and driven by anoil pressure, and raises and lowers the neck mold 73 with respect to theinjection cavity mold 75 by use of the actuator 78 a as a power source.In detail, the actuator 78 a allows a neck mold moving plate 85, towhich the neck mold 73 has been fixed, to make an ascending ordescending motion via a neck mold raising/lowering plate 86 and tie bars87. The mold clamping drive portion 79 has an actuator 79 a composed ofa hydraulic cylinder or the like fixed inside the machine stand 80 anddriven by an oil pressure, and clamps the closed injection mold 71 at ahigh pressure by use of the actuator 79 a as a power source.

The opening/closing drive portion 77, the raising/lowering drive portion78, and the mold clamping drive portion 79 have mechanisms of existingconfigurations, and thus their detailed explanations are omitted herein(if they are necessary, reference is requested to the official gazetteof a prior application by the present applicant (e.g., Japanese PatentNo. 4319863)).

The blow molding section 40 is equipped with a blow mold unit 41including a blow mold 42 for blow molding the preform, and a blow molddrive unit 43. The blow mold 42, as shown in FIG. 3, is composed of aneck mold 44 for holding a neck of a hollow container 2, a pair ofopenable and closable blow split molds 45 for forming the outer shape ofa barrel of the hollow container 2, and a blow bottom mold 46 forforming the bottom shape of the hollow container.

In the blow molding section 40, such a blow mold 42 is opened, closedand clamped by the blow mold drive unit 43, and a stretching rod 47 andhigh pressure air are introduced into the preform disposed inside toperform biaxial stretch blow molding of the preform, thereby forming thehollow container 2.

The blow mold drive unit 43 has an opening/closing drive portion 48 formold opening, closing and clamping the pair of blow split molds 45, anda raising/lowering drive portion 49 for raising and lowering the blowbottom mold 46. Concretely, the opening/closing drive portion 48 hasactuators 48 a, 48 b constituted by hydraulic cylinders or the like tobe driven by an oil pressure, and these actuators 48 a, 48 b areconnected to the paired blow split molds 45. The raising/lowering driveportion 49 has an actuator 49 a constituted by a hydraulic cylinder orthe like to be driven by an oil pressure, and this actuator 49 a isconnected to the blow bottom mold 46.

The blow mold drive unit 43 (actuators 48 a, 48 b, 49 a), the injectionmold drive unit 72 (actuators 77 a, 78 a, 79 a), and the injection driveunit 63 (injecting hydraulic motor 64 and injecting hydraulic cylinder65) are actuated when supplied with oil from an oil tank 90.

The injection blow molding apparatus 10 according to the presentinvention is equipped with a plurality of oil supply sections 100 forsupplying oil (working fluid) within the oil tank 90 to the blow molddrive unit 43, the injection mold drive unit 72, and the injection driveunit 63. In the present embodiment, the injection blow molding apparatus10 has 3 of the oil supply sections 100 (first to third oil supplysections 100A, 100B, 100C) (see FIG. 1).

Each of the first to third oil supply sections 100A, 100B and 100C isprovided with a hydraulic drive source composed of a drive motor 101(101A, 101B, 101C) whose number of revolutions can be controlled, and ahydraulic pump 102 (102A, 102B, 102C), and adjusts the flow rate of oil(discharge flow rate) and the pressure of oil (discharge pressure), theoil discharged from the hydraulic pump 102, based on the number ofrevolutions and the torque of the drive motor 101 controlled by acontroller 110. The drive motor 101 may be a motor having the number ofrevolutions controllable and, a servo motor or an inverter motor, forexample, is used suitably. In the present embodiment, a servo motor withhigher responsiveness than other motors is adopted as the drive motor101. A fixed discharge type hydraulic pump is employed as the hydraulicpump 102. That is, in the present embodiment, each of the first to thirdoil supply sections 100A, 100B, 100C has a so-called servo pump as ahydraulic drive source. In consideration of a reduction in the initialcost of the apparatus, moreover, use is made of the three hydraulicdrive sources (servo pumps) constituting the oil supply sections 100A,100B, 100C which exhibit the same performance.

In the present embodiment, the first oil supply section 100A isconnected to the injection mold drive unit 72 (actuators 77 a, 78 a, 79a) provided in the injection mold unit 70 via a hydraulic circuit 120A.In the hydraulic circuit 120A, a pressure control valve, a flow controlvalve, a direction control valve, etc. are arranged, as appropriate,although their illustrations are omitted. By controlling these controlvalves, as appropriate, oil is supplied from the first oil supplysection 100A to the respective actuators 77 a, 78 a, 79 a.

The second oil supply section 100B is provided independently of thefirst oil supply section 100A, and is connected to the blow mold driveunit 43 (actuators 48 a, 48 b, 49 a) provided in the blow mold unit 41via a hydraulic circuit 120B. Further, the third oil supply section 100Cis provided independently of the first oil supply section 100A and thesecond oil supply section 100B, and is connected to the injection driveunit 63 (injecting hydraulic motor 64 and injecting hydraulic cylinder65) of the injection device 60 via a hydraulic circuit 120C.

The injection blow molding apparatus 10 according to the presentinvention has the plurality of oil supply sections 100A, 100B, 100Cwhich are independent of each other and which have the hydraulic drivesources composed of the drive motors 101, such as servo motors orinverter motors, and the hydraulic pumps 102. That is, the first tothird oil supply sections 100A, 100B and 100C can be controlledindependently. Also, the first to third oil supply sections 100A, 100Band 100C supply oil to the different drive units 43, 72, 63 to actuatetheir respective actuators. By so doing, the number of revolutions ofthe drive motors 101A, 101B, 101C constituting the first to third oilsupply sections 100A, 100B and 100C can be individually decreased inaccordance with the required loads of the drive units 43, 72, 63. Thus,the energy saving properties of the injection blow molding apparatus 10can be improved.

With the conventional injection blow molding apparatus, on the otherhand, the hydraulic pumps for the blow mold drive unit, the injectionmold drive unit, and the injection device are driven by one inductionmotor. Thus, even when it is attempted to simply decrease the amount ofthe hydraulic oil in the injection mold drive unit, for example, thedischarge amount is unchanged (in the case of the fixed pump), becausethe number of revolutions of the induction motor is constant. Hence, itis necessary to drive, as appropriate, the various control valvesarranged in the hydraulic circuit, thereby adjusting the flow rates.This also influences the hydraulic circuits for the blow mold drive unitand the injection device. As a result, the amount of the pressure oildiscarded without being used in each actuator is also increased, thusgenerally resulting in a low energy efficiency.

With the injection blow molding apparatus 10 according to the presentinvention, moreover, each of the oil supply sections 100A, 100B, 100Chas the hydraulic drive source composed of the drive motor 101, such asa servo motor or an inverter motor, and the hydraulic pump 102, asmentioned above. According to this configuration, the number ofrevolutions of each of the drive motors 101A, 101B, 101C can bedecreased appropriately and individually when the required loads of thedrive units 43, 72, 63 are low. Hence, noises during operation of theapparatus can be reduced. That is, the low-noise properties of theinjection blow molding apparatus 10 can be improved.

The oil supply sections 100A, 100B, 100C are configured to beindependent of, and not to be dependent on, each other. Thus, they canindividually control the oil pressures (adjust the hydraulic pressurewaveforms) of the respective hydraulic drive units including the blowmold drive unit 43, injection mold drive unit 72, and injection device63. If there is any problem, or point to be improved, in the operatingbehavior or operating time of any of the hydraulic drive units,therefore, it is sufficient to adjust the hydraulic pressure waveform orthe like of only the hydraulic drive unit at issue, thus facilitating ameasure for solving the problem. Consequently, the operating trouble ofthe injection blow molding apparatus 10 as a whole is also easy toeliminate as compared with the conventional injection blow moldingapparatus. Furthermore, the operating time of the entire injection blowmolding apparatus 10 can be shortened, and its energy saving propertiescan be improved, in comparison with the conventional injection blowmolding apparatus.

Besides, the work efficiency of molding adjustment, etc. is increased.Since the first to third oil supply sections 100A, 100B, 100C areindependent of each other, it is possible to exercise control over therespective oil supply sections; for example, it is possible to adjustthe oil pressure-related parameters, such as gain, response speed, andcommand pressure, individually and optimally. Hence, the pressure of oil(oil pressure, hydraulic pressure) supplied to each actuator can beadjusted more appropriately.

FIGS. 5A, 5B are time-varying hydraulic pressure waveform charts showingchanges in a command pressure P1 required of the first oil supplysection 100A in the injection molding step, and changes in an actualpressure P2 given by the first oil supply section 100A based on thecommand pressure P1, FIG. 5A showing the state before adjustment, andFIG. 5B showing the state after adjustment. The actual pressure P2 isthe sum of the values detected by oil pressure gauges (not shown)provided near the actuators 77 a, 78 a, 79 a in the hydraulic circuit120A.

The hydraulic pressure waveform charts in FIGS. 5A, 5B show the commandpressure P1 and the actual pressure P2 during a cycle of the injectionmolding step, starting from a state in which the injection mold 71 hasbeen clamped. First, during the period from a time T1 to a time T2, theactuator 79 a is actuated (retreated) to complete the clamping of theinjection mold 71. During the period from the time T2 to a time T3, theactuators 77 a, 78 a are actuated (retreated) to carry out the openingof the injection mold 71. Then, during the period from the time T3 to atime T4, transport of the injection-molded preform is performed. Duringthe period from the time T4 to a time T5, the actuators 77 a, 78 a areoperated (advanced) to close the injection mold 71 again. During theperiod from the time T5 to a time T6, the actuator 79 a is operated(advanced) to perform the clamping of the injection mold 71.

Such a series of actions of the injection mold drive unit 72 (actuators77 a, 78 a, 79 a) is controlled by the first oil supply section 100A(drive motor 101A), as stated earlier. The first oil supply section 100Acontrols only the actions of the injection mold drive unit 72. Thus, thedischarge pressure and the discharge amount, etc. by the first oilsupply section 100A can be adjusted more appropriately in conformitywith the actions of the injection mold drive unit 72.

Concretely, the first oil supply section 100A is capable of adjustmentof the command pressure, etc. through a plurality of (e.g., four)channels. Since the first oil supply section 100A controls only theactions of the injection mold drive unit 72 as mentioned above, it canassign all of the four channels for the injection mold drive unit 72.Hence, the control over the discharge pressure, etc. by the first oilsupply section 100A can be adjusted more appropriately in conformitywith the actions of the injection mold drive unit 72.

For example, the first oil supply section 100A (drive motor 101A) iscontrolled to provide the command pressure P1, but the actual pressureP2 may deviate from the command pressure P1 because of the occurrence ofa surge pressure. In the example shown in FIG. 5A, a surge pressureoccurs, for example, at the time Ta, the time Tb, and the time Tc, withthe result that the actual pressure P2 deviates from the commandpressure P1. Even in such a case, settings are made such that the timeTa, the time Tb, and the time Tc when these surge pressures occur belongto different channels. By so doing, the surge pressures occurring at aplurality of timings can be reduced appropriately.

In the examples of FIGS. 5A, 5B, one cycle of the injection molding stepis assigned to the four channels, Channel Nos. 0 to 3. The periodincluding the time Ta is assigned to Channel No. 3, the period includingthe time Tb is assigned to Channel No. 0, and the period including thetime Tc is assigned to Channel No. 1.

In Channel No. 3, therefore, control of the first oil supply section100A can be adjusted in accordance with the magnitude of the surgepressure at the time Ta. In Channel No. 0, control of the first oilsupply section 100A can be adjusted in accordance with the magnitude ofthe surge pressure at the time Tb. In Channel No. 1, control of thefirst oil supply section 100A can be adjusted in accordance with themagnitude of the surge pressure at the time Tc. By these measures, thesurge pressures at the time Ta, time Tb and time Tc can be effectivelysuppressed, as shown in FIG. 5B. By adjusting and reducing suchundesirable hydraulic pressure waveforms, the operating rate of thedrive motor 101A can be decreased. As a result, the power consumptionper cycle of molding can be reduced and, further, the operating time ofthe injection mold drive unit 72 can also be shortened.

How to assign the channels is not particularly limited, and may bedetermined, as appropriate, in accordance with the actual pressure P2 orthe like.

The present invention has been described above in connection with itsone embodiment, but it is to be understood that the invention is in noway limited to this embodiment. The present invention can be changed ormodified, as appropriate, without departing from its spirit and scope.

EXPLANATIONS OF LETTERS OR NUMERALS

-   -   1 Preform    -   2 Hollow container    -   10 Injection blow molding apparatus    -   20 Injection molding section    -   30 Temperature control section    -   40 Blow molding section    -   41 Blow mold unit    -   42 Blow mold    -   43 Blow mold drive unit    -   43 a Actuator    -   44 Neck mold    -   45 Blow split mold    -   46 Blow bottom mold    -   47 Stretching rod    -   48 Opening/closing drive portion    -   48 a, 48 b Actuator    -   49 Raising/lowering drive portion    -   49 a Actuator    -   50 Withdrawal section    -   60 Injection device    -   61 Injection cylinder    -   62 Injection screw    -   63 Injection drive unit    -   64 Injecting hydraulic motor    -   65 Injecting hydraulic cylinder    -   70 Injection mold unit    -   71 Injection mold    -   72 Injection mold drive unit    -   73 Neck mold    -   74 Injection core mold    -   75 Injection cavity mold    -   76 Hot-runner mold    -   77 Opening/closing drive portion    -   77 a Actuator    -   78 Raising/lowering drive portion    -   78 a Actuator    -   79 Mold clamping drive portion    -   79 a Actuator    -   90 Oil tank    -   100 Oil supply section    -   101 Drive motor (servo motor)    -   102 Hydraulic pump    -   110 Controller    -   120 Hydraulic circuit

The invention claimed is:
 1. An injection blow molding apparatus,comprising: an injection molding section configured to form a preform byinjection molding, the injection molding section including: an injectionunit; and an injection mold unit configured to be operated by an oilpressure; a blow molding section configured to blow mold the preform andincluding a blow mold unit; a first oil supply section including ahydraulic drive source and configured to supply oil from an oil tank toan injection mold drive unit of the injection mold unit, the hydraulicdrive source including: a drive motor, whose number of revolutions isconfigured to be controlled; and a hydraulic pump; and a controllerconfigured to control the number of revolutions of the drive motor ofthe first oil supply section, wherein the controller is configured tocontrol the first oil supply section to set a target pressure of oildischarged from the hydraulic pump as a command pressure, wherein onecycle of an injection molding operation is assigned to a plurality ofchannels, and wherein, when an actual pressure of oil supplied from thefirst oil supply section deviates from the command pressure, thecontroller adjusts the command pressure in each channel in accordancewith a magnitude of a difference between the actual pressure and thecommand pressure, and the adjustment of the command pressure in eachchannel being independent of each other.
 2. The injection blow moldingapparatus according to claim 1, further comprising: a third oil supplysection including a hydraulic drive source and configured to supply oilfrom the oil tank to an injection drive unit of the injection unit, thehydraulic drive source including: a drive motor, whose number ofrevolutions is configured to be controlled; and a hydraulic pump,wherein the third oil supply section is provided independently of thefirst oil supply section, and wherein the controller, which isconfigured to control the number of revolutions of the drive motor ofthe first oil supply section, is configured to control the number ofrevolutions of the drive motor of the third oil supply section.
 3. Theinjection blow molding apparatus according to claim 2, furthercomprising: a second oil supply section including a hydraulic drivesource and configured to supply oil from the oil tank to a blow molddrive unit of the blow mold unit, the hydraulic drive source including:a drive motor, whose number of revolutions is configured to becontrolled; and a hydraulic pump, wherein the second oil supply sectionis provided independently of the first oil supply section and the thirdoil supply section, and wherein the controller, which is configured tocontrol the number of revolutions of the drive motor of the first oilsupply section and the number of revolutions of the drive motor of thethird oil supply section, is configured to control the number ofrevolutions of the drive motor of the second oil supply section.
 4. Theinjection blow molding apparatus according to claim 1, wherein the drivemotor is a servo motor.
 5. The injection blow molding apparatusaccording to claim 4, wherein the injection mold unit comprises aninjection mold including: a neck mold for forming a neck portion of thepreform; an injection core mold for forming an inner shape of thepreform; and an injection cavity mold for forming an outer shape of abarrel portion of the preform, wherein the injection mold drive unitincludes: an opening/closing drive portion for opening and closing theinjection mold; a raising/lowering drive portion for raising andlowering the neck mold with respect to the injection cavity mold; and amold clamping drive portion for clamping the injection mold which hasbeen closed, and wherein the first oil supply section is configured tosupply oil from the oil tank to the opening/closing drive portion, theraising/lowering drive portion, and the mold clamping drive portion. 6.An injection blow molding apparatus comprising: an injection moldingsection configured to form a preform by injection molding, the injectionmolding section including: an injection unit configured to be operatedby an oil pressure; and an injection mold unit configured to be operatedby an oil pressure; a blow molding section configured to blow mold thepreform and including a blow mold unit; a first oil supply sectionincluding a hydraulic drive source and configured to supply oil from anoil tank to an injection mold drive unit of the injection mold unit, thehydraulic drive source including: a drive motor, whose number ofrevolutions is configured to be controlled; and a hydraulic pump; athird oil supply section including a hydraulic drive source andconfigured to supply oil from the oil tank to an injection drive unit ofthe injection unit, the hydraulic drive source including: a drive motor,whose number of revolutions is configured to be controlled; and ahydraulic pump, the third oil supply section being providedindependently of the first oil supply section; and a controllerconfigured to control the number of revolutions of the drive motor ofthe first oil supply section and the number of revolutions of the drivemotor of the third oil supply section.
 7. The injection blow moldingapparatus according to claim 6, wherein the drive motor is a servomotor.